Blasting operations

ABSTRACT

This invention relates to a device for maintaining a detonator and its associated firing connection in position relative to an explosive charge while the latter is inserted into a previously prepared hole during blasting operations. The device comprises an elongated member divided into two arms by a generally rightangled bend, the free end of one arm having a spike extending substantially parallel to the other arm which has at its free end a clip adapted to frictionally engage a fuse or detonating wire extending roughly parallel to said first arm, said arms being flexible but substantially non-deformable.

nited States Patent [191 Rose Jan. 8, 1974 BLASTING OPERATIONS PrimaryExaminer-Verlin R. Pendegrass 76 I t Nathan 1 G. Rose 12 T Rd. 1 men orMountgienview, gfig Attomey-Watson, Cole, Grindle & Watson Africa 221Filed: Mar. 14, 1972 [57] ABSTRACT This invention relates to a devicefor maintaining a [21] Appl' 9 234,564 detonator and its associatedfiring connection in position relative to an explosive charge while thelatter is [30] F i A li i P i i D inserted into a previously preparedhole during blast- Mar. 15 197! south Africa 71/1675 ing operations. Thedevice comprises an elongated member divided into two arms by agenerally right- [52] US. Cl 102/28 A angled bend the free end of one amhaving a Spike 511 Int. Cl. F42b 3/10 extending Substantially Parallelthe which [58] Field of 102/22 28 A has at its free end a clip adaptedfricthhahy engage a fuse or detonating wire extending roughly parallelto [56] References Cited said first arm, said arms being flexible butsubstantially FOREIGN PATENTS OR APPLICATIONS 11/1945 Great Britain102/28 A non-deformable.

13 Claims, 3 Drawing Figures BLASTING OPERATIONS This invention relatesto blasting operations using dynamite or like sticks as the explosivecharge and more particularly the invention relates to a device formaintaining a detonator and its associated fuse or electric wire inposition relative to a stick of dynamite while the latter is insertedinto a drilled holed therefor.

Devices of this type presently used or proposed are either costly,ineffective or at least difficult to install. It is thus the object ofthis invention to provide a device which is inexpensive to manufacture,effective in use and simple to install.

In accordance with this invention there is provided a device of theabove-described general type comprising an elongated member divided intotwo arms by a generally right-angled bend, the free end of one armhaving a spike extending substantially parallel to the other arm whichhas at its free end a clip adapted to frictionally engage a fuse ordetonating wire extending roughly parallel to said first arm, said armsbeing flexible but substantially non-deformable.

Further features of the invention provide for the device to be moldedfrom synthetic plastics material, preferably polypropylene, for the armsto be of T-shape in cross-section with the stem of the T on the outsideof the right-angled bend, for one of the arms to be provided with anenlarged smooth area at the rear end of the spike. The spike todecreases in cross-sectional area towards its point and is of acruciform in cross-section, and the clip is a collar having a slot inthe side thereof allowing the transverse introduction of a fuse ordetonator wire therein.

A preferred embodiment of the invention will now be described by way ofexample, reference being made to the accompanying drawings in which:

FIG. 1 is an isometric view of the device;

FIG. 2 is a sectional view taken along line A-A in FIG. 1; and

FIG. 3 is an elevation of the device in use.

In this embodiment of the invention the device is molded frompolypropylene which has the advantage over polyvinyl chloride which hasbeen previously used in that nochlorine or hydrogen chloride gas isgiven off when the plastics material is burnt.

The device comprises an elongated member 1 divided into two arms 2 and 3of different lengths by a right-angled bend 4. The longer arm 3 has atits free end a disc shaped formation 5 carrying a spike 6 extendingparallel to, andin the same direction as, the shorter arm 2. This spike6 is of a cruciform in crosssection and decreases constantly incross-sectional area towards the point 7 thereof.

The free end of the shorter arm is provided with a sleeve 8 having aslot 9 inthe sidewall thereof, the axis of the sleeve being parallel tothe longer arm 3. The sleeve and slot are dimensioned such that afuse'or detonator wire may be clipped transversely into the sleeve to befrictionally engaged thereby. Also the sleeve is connected to the arm 2at its end farthest removed from the spike so that it projectsdownwardly toward the latter.

The elongated member 1 is made to a T-shape in cross-section with thestem of the T located on the outside of the member as shown clearly inFIG. 2. This shape allows sufficient flexibility while ensuring that themember will not be permanently deformed under normal bending thereof.

In use, a fuse 10 or detonator wire connected to a detonator 11 isclipped into the sleeve 8 in a position such that the detonator may beinserted to the normal depth in a stick of dynamite 12. The detonator isthen inserted and the longer arm flexed such that the point of the spikerests on the outside of the stick of dynamite, the spike is then pushedinto the dynamite manually, the outer surface of the disc providing acomfortable area for a persons thumb.

If the spike enters the dynamite too far from the end thereof, thesleeve will tend to enter the dynamite instead of the shorter armpivoting outwardly about the corner of the stick of dynamite as is thecase with presently proposed molded devices.

The invention therefore provides a useful, effective and inexpensivedevice of this type.

It may be found that the spike above described will tend to pull out ofthe dynamite and if this is the case, it is easily remedied by removingthe portion 13 of one of the fins 14 of the spike (defined by the armsof the X) adjacent the disc 5, thus forming a type of barb. The finnearest the sleeve is preferred for this purpose, since generally theforce on the device will be axially away from the dynamite which willcause this barb to dig into the dynamite.

What I claim as new and desire to secure by Letters Patent is:

1. A device comprising an elongated member divided into two arms by agenerally right-angled bend, the free end of one of said arms having aspike extending substantially parallel to the other of said arms whichhas at its free end a tubular collar extending parallel to said firstarm and having a slot in the side wall thereof is adapted tofrictionally engage a fuse or detonating wire extending substantiallyparallel to said first arm, said arms being flexible and substantiallynon-deformable.

2. A device as claimed in claim 1 in which the device is made as anintegral plastics molding.

3. A device as claimed in claim 2 in which the plastics material ispolypropylene.

4. A device as claimed in claim 1 in which the arms are of T-shape incross-section with the stem of the T on the outside of the bend.

5. A device as claimed in claim 1 in which said one arm is provided withan enlarged smooth area at the rear end of the spike and is arrangedtransversely thereto.

6. A device as claimed in claim 1 in which the spike decreases incross-sectional area towards its point.

7. A device as claimed in claim 1 in which the con nector between thecollar and arm to which it is connected is remote from said spike.

8. A device comprising an elongated member divided into two arms by agenerally right-angled bend, the free end of one of said arms having aspike extending substantially parallel to the other of said arms, saidspike having fins defining a shape of cruciform cross-section, one ofsaid fins having an interruption thereon to thereby provide a barb forsaid spike, the free end of the other of said arms having a clip thereonadapted to frictionally engage a fuse or detonating wire extendingsubstantially parallel to said first arm, said arms being flexible andsubstantially non-deformable.

9. A device according to claim 8 in which said elongate member is madeas an integral plastic molding.

arm is provided with an enlarged smooth area at the rear end of thespike and is arranged transversely thereto.

13. A device as in claim 8 in which the spike decreases incross-sectional area toward its point.

1. A device comprising an elongated member divided into two arms by agenerally right-angled bend, the free end of one of said arms having aspike extending substantially parallel to the other of said arms whichhas at its free end a tubular collar extending parallel to said firstarm and having a slot in the side wall thereof is adapted tofrictionally engage a fuse or detonating wire extending substantiallyparallel to said first arm, said arms being flexible and substantiallynon-deformable.
 2. A device as claimed in claim 1 in which the device ismade as an integral plastics molding.
 3. A device as claimed in claim 2in which the plastics material is polypropylene.
 4. A device as claimedin claim 1 in which the arms are of T-shape in cross-section with thestem of the T on the outside of the bend.
 5. A device as claimed inclaim 1 in which said one arm is provided with an enlarged smooth areaat the rear end of the spike and is arranged transversely thereto.
 6. Adevice as claimed in claim 1 in which the spike decreases incross-sectional area towards its point.
 7. A device as claimed in claim1 in which the connector between the collar and arm to which it isconnected is remote from said spike.
 8. A device comprising an elongatedmember divided into two arms by a generally right-angled bend, the freeend of one of said arms having a spike extending substantially parallelto the other of said arms, said spike having fins defining a shape ofcruciform cross-section, one of said fins having an interruption thereonto thereby provide a barb for said spike, the free end of the other ofsaid arms having a clip thereon adapted to frictionally engage a fuse ordetonating wire extending substantially parallel to said first arm, saidarms being flexible and substantially non-deformable.
 9. A deviceaccording to claim 8 in which said elongate member is made as anintegral plastic molding.
 10. A device as claimed in claim 9 in whichthe plastic material is polypropelene.
 11. A device as in claim 8 inwhich the arms are of T-shape in cross-section with the stem of the Tbeing located on the outside of the bend.
 12. A device as claimed inclaim 8 in which said one arm is provided with an enlarged smooth areaat the rear end of the spike And is arranged transversely thereto.
 13. Adevice as in claim 8 in which the spike decreases in cross-sectionalarea toward its point.